DNA–Cu(II) poly(amine) complex membrane as novel catalytic layer for highly sensitive amperometric determination of hydrogen peroxide

• Published in: Biosensors & bioelectronics 2006-05, Vol.21 (11), p.2121-2128
• Main Authors: Gu, Tingting, Hasebe, Yasushi
• Format: Article
• Language: English
• Subjects: Amperometric biosensor; Animals; Biological and medical sciences; Biosensing Techniques - methods; Biosensors; Biotechnology; Catalysis; Copper; DNA; DNA–Cu(II) complex; DNA–poly(amine) membrane; Electric Conductivity; Electrochemistry; Fundamental and applied biological sciences. Psychology; Hydrogen peroxide; Hydrogen Peroxide - analysis; Male; Membranes, Artificial; Methods. Procedures. Technologies; Microscopy, Atomic Force; Polyamines; Salmon - genetics; Sensitivity and Specificity; Testis - chemistry; Various methods and equipments
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2005.10.007

A novel hydrogen peroxide biosensor was fabricated by using a DNA–Cu(II) complex as a novel electrocatalyst for the reduction of hydrogen peroxide (H2O2). A polyion complex (PIC) membrane composed of DNA and poly(allylamine) (PAA) functioned as a support matrix for immobilization of electrocatalytic element-copper ion. The circular dichroism (CD) spectrum of the DNA–Cu(II)/PAA membrane in wet state showed that the DNA exists in B-like form within the membrane. Electrochemical measurements of the DNA–Cu(II)/PAA membrane-modified glassy carbon (GC) electrode revealed that the copper ion embedded in the DNA/PAA layer exhibits good electrochemical behaviors, and the electrochemical rate constant between the immobilized copper ion and the GC electrode surface was estimated to be 26.4s−1. The resulting DNA–Cu(II)/PAA/GC electrode showed an excellent electrocatalytic activity for the H2O2 reduction. The sensitivity of the sensor for the determination of H2O2 was affected by the amount of each component, such as copper ion, DNA and PAA in the DNA–Cu(II)/PAA membrane. Effects of applied potential, pH, temperature, ionic strength and buffer concentrations upon the response currents of the sensor were also investigated for an optimum analytical performance. Even in the presence of dissolved oxygen, the sensor exhibited highly sensitive and rapid (response time, less than 5s) response to H2O2. The steady-state cathodic current responses of the sensor obtained at −0.2V versus Ag/AgCl in air-saturated 50mM phosphate buffer (pH 5.0) increased linearly up to 135μM with the detection limit of 50nM. Interference by ascorbic acid and uric acid due to the reduction of Cu(II) was effectively cancelled by further modification of outermost layer of polyion complex film. In addition, the sensor exhibited good reproducibility and stability.